Sounds to me like this:
Issue 1:
Heater control valve is screwed up, stuck closed, or the heater core has been bypassed due to a leak.
(heater cores can be a bear to change on our vans.)
Issue 2:
It could be a bad ground, but I'd have to look at a wiring diagram to figure that one out.
I'd find any common grounding points, then bypass them to see if the problems stop.
Issue 3:
Use the manual with the wiring diagram in it (that you bought from Issue 2
) to find the color designations to the wires.
That would be how I would approach your issues.
(I love the wire on the ash tray starting trick
)